1. Field of the Invention
The present invention relates to novel 1-(3,4,5-trimethoxycinnamoyl)-4-aminocarbonylethyl-substituted piperazine derivatives and pharmaceutically acceptable acid addition salts thereof which exhibit an effective vasodilatory activity, and to a process for the preparation thereof, pharmaceutical compositions thereof, and method of treating therewith.
Particularly, this invention relates to novel 1-(3,4,5-trimethoxycinnamoyl)-4-aminocarbonylethyl-substituted piperazine derivatives represented by general formula (I): ##STR2## wherein R is a straight- or branched-chain alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms, and pharmaceutically acceptable acid addition salts thereof, a process for the preparation thereof, pharmaceutical compositions thereof, and method of treating therewith.
2. Description of the Prior Art
Many vasodilators have been already researched and developed, but there are still problems which should be improved with regard to drug effects and side effects.
For example cinepazide (general name, Merck Index, 9th Edition, 2282), represented by formula (II): ##STR3## is well known as a vasodilator and has been widely provided for clinical use.
However, cinepazide suffers from the defect that, while the toxicity is low, the drug effect is weak.
For purposes of improving the vasodilatory action of cinepazide represented by formula (II), cinpropazide (general name, USAN and the USP Dictionary of Drug Names, 1982, page 109) represented by formula (III): ##STR4## has been prepared. It was found that the toxicity became greater while the drug effect became stronger. Therefore, it was difficult to provide for clinical use.